ch 16 mastering A&P2 - endocrine
Your patient has been diagnosed with Type I diabetes mellitus, and you are explaining how to administer insulin. Your patient states, "I don't want to do this. My brother-in-law has diabetes, and he just takes a pill and watches what he eats." What is your best response?
"Your relative may have Type II diabetes. People with that condition can make insulin, but their cells don't respond to it properly. Your pancreas doesn't manufacture insulin."
What is the mechanism of action of lipid-soluble hormones?
activation of genes, which increases protein synthesis in the cell Yes, lipid-soluble hormones diffuse into the nucleus or they diffuse into the cytoplasm and then move into the nucleus, where they affect transcription and translation.
After a lipid-soluble hormone is bound to its intracellular receptor, what does the hormone complex do?
acts as a transcription factor and binds to DNA, activating a gene Yes, then mRNA is synthesized.
What hormone, indicated by letter B, is released by the anterior pituitary to target the adrenal cortex when the body is under stress?
adrenocorticotropic hormone (ACTH) Adrenocorticotropic hormone (ACTH) from the pituitary modulates the release of aldosterone. The term tropic refers to a hormone that acts on another endocrine gland.
What tropic hormone stimulates cortisol from the adrenal gland?
adrenocorticotropic hormone (ACTH) Yes, ACTH stimulates the adrenal cortex to produce cortisol. Stress and ACTH are the main stimuli for cortisol.
____ : Targets the adrenal gland to release glucocorticoids and mineralocorticoidstarget 4 of 5
adrenocortropic hormone
____ : Increased sodium and water absorption
aldosterone
The word root _____ means blood or lymph vessels.
angio
Upon the release of renin, ______ is produced and stimulates vasoconstriction and the release of aldosterone.
angiotensin II
Which hormone aids in water resorption?
antidiuretic hormone Antidiuretic hormone (ADH) stimulates the kidney tubules to reabsorb water.
What hormone released into the blood by the posterior pituitary would reduce the amount of urine that is formed?
antidiuretic hormone (ADH) Antidiuretic hormone (ADH) targets the kidneys and modulates how much water is lost in the urine.
The amplification of the signal from a water-soluble hormone is achieved through an increase in _______.
cAMP in the cytoplasm Many cAMP can be generated as a second messenger to amplify the signal in response to hormone binding.
What hormone is released by the cells pictured in letter D?
calcitonin These humorally-stimulated cells respond to increasing levels of calcium in the blood and secrete calcitonin to counteract it.
What keeps intracellular receptors from binding to DNA before a hormone binds to the receptor?
chaperone proteins (chaperonins) Yes, each receptor has two binding sites. The chaperone protein blocks the DNA binding site until a hormone binds at the hormone binding site.
What is the function of the ventral hypothalamic neurons?
control secretion of thyroid stimulating hormone (TSH) Yes, neurohormones from the ventral hypothalamic neurons, known as releasing (RH) and inhibiting (IH) hormones, control the release of anterior pituitary hormones such as adrenocorticotropic hormone (ACTH) and TSH.
____: Stimulates the anterior pituitary to release ACTH
corticotropin-releasing hormone
____ : Increased metabolic effects from the liver
cortisol
Which of the following hormones has intracellular receptors?
cortisol Yes, cortisol is one of the lipid-soluble steroid hormones. Thyroid hormones are also lipid soluble.
Glucose levels in the blood are tightly controlled. An important hormone for controlling blood glucose is insulin, which is released by the pancreas. Increases in blood glucose cause insulin release. This is an example of a hormone released in response to a _____ stimulus. Insulin release is terminated when blood glucose ____. This is an example of _____ feedback
humoral, falls, and negative
Where is antidiuretic hormone (ADH), also known as vasopressin, synthesized?
hypothalamus Yes, ADH is synthesized mainly in the supraoptic nucleus of the hypothalamus. It is stored in the posterior pituitary in axon terminals.
What is the most important regulatory factor controlling the circulating levels of thyroid hormone?
negative feedback Yes, negative feedback controls the levels of circulating thyroid hormone. If levels are high, negative feedback will decrease thyroid-stimulating hormone (TSH) (and thyrotropin-releasing hormone (TRH) to some degree), thus decreasing the thyroid hormones.
Which of the following hormones is regulated by a neuroendocrine ("letdown") reflex?
oxytocin Yes, suckling of the infant (or stretching of the uterus) increases release of oxytocin, which causes the milk let-down effect (or increased uterine contractions).
Which hormone's receptor is always bound to DNA, even when the receptor is empty?
thyroid hormone Yes, thyroid hormones are lipid soluble and their receptors are bound to the response elements of the DNA.
The word root _____ means attracted specifically to the specified organ or tissue.
tropic
The various hormones secreted by the anterior pituitary that regulate the secretion of hormones from other endocrine organs are called __________.
tropins Four of the six anterior pituitary hormones—thyroid-stimulating hormone (thyrotropin), adrenocorticotropic hormone (corticotropin), follicle-stimulating hormone and luteinizing hormone (gonadotropins)—are tropins (tropic hormones) that regulate the secretory action of other endocrine glands.
The word root ____ means urine
uria
Jeremy has been feeling tired and cold for the last week. His roommate offers Jeremy his bottle of thyroid hormone supplements and promises that they will make him feel better (they don't). Suppose that Jeremy's thyroid hormone levels were normal to start with, and that the supplements actually did contain active thyroid hormones. After taking these supplements for a week, how do you think Jeremy's blood levels of thyroid-stimulating hormone (TSH) and thyrotropin-releasing hormone (TRH) would compare to normal levels?
Both TSH and TRH would be lower than normal Thyroid hormone release follows the pattern of a hormonal stimulus for hormone release. When thyroid hormone levels go up, there is increased negative feedback on both TRH from the hypothalamus and TSH from the anterior pituitary, so blood levels of these hormones decrease.
Where are the hormones oxytocin and antidiuretic hormone (ADH) stored?
C The axon terminals of neurons of the hypothalamic-hypophyseal tracts store and secrete ADH and oxytocin in the capillaries of the inferior hypophyseal artery.
Insulin-like growth factors (IGFs) are intermediary hormones stimulated by which of the following hormones?
GH (growth hormone) Yes, GH stimulates IGFs from the liver. IGFs are required for the growth effect of GH on bone and skin.
How do endocrine hormones reach their target cells?
Hormones are transported through the blood stream to target cells. The blood stream allows hormones to be distributed throughout the body.
___ : Increased dilation of bronchioles and heart rate
epinephrine
A patient is being treated by her urologist for a fourth episode of kidney stones. Analysis of the stones shows that they are composed of calcium oxalate. The urologist orders an assay of which hormone?
Parathyroid hormone (PTH) Inappropriately high levels of PTH may result in excess calcium in the blood, which might precipitate in the urine. The result is renal lithiasis, or kidney stones.
Hypocalcemia could be caused by the ______.
Parathyroid hormone (parathormone) is secreted in response to hypocalcemia. It functions to stimulate osteoclast activity, enhances the reabsorption of calcium by the kidneys, and increases absorption of calcium ions by the intestinal mucosal cells.
FSH and LH are examples of _______ hormones, which target the ovaries or testes.
gonadotropic
What is the role of activated protein kinases?
Phosphorylate proteins. Phosphorylation can activate different proteins causing the response of the cell to water-soluble hormone.
Which letter represents the hormone that promotes a decrease in blood pressure and increases the excretion of sodium and water in urine?
The letter D indicates atrial natriuretic peptide, which is released from the heart when high blood pressure is sensed. It causes more sodium ("natrium") to be placed in the urine ("uretic").
As the adrenal gland releases glucocorticoids, which of the following effects may be observed? Select all the answers that apply.
- Decrease in immune system function - Increased blood glucose levels - Lipid breakdown in the liver will increase - Increased blood levels of amino acids With long-term stress, the glucocorticoid hormones, chiefly cortisol, are instrumental in the body. The primary targets include the liver, resulting in increased gluconeogenesis and increased catabolism of lipids and proteins. In larger amounts, the depression of the immune system can result.
Drag and drop the items below into the correct sequence from left to right.
1.Hypothalamus secretescorticotropin-releasinghormone 2.Corticotropin-releasinghormone travels throughthe portal system to theanterior pituitary 3.Adrenocorticotropichormone is secreted fromthe anterior pituitary 4.ACTH travels in the bloodto the adrenal cortex 5.Glucocorticoids andmineralocorticoidsare secreted 6.Target cells producemetabolic and renal effects In the long-term stress response, stressful stimuli cause the hypothalamus to release corticotropin-releasing hormone, or CRH. CRH then travels through the hypothalamic portal system to the anterior lobe of the pituitary gland. The anterior pituitary releases adrenocorticotropic hormone, or ACTH, which travels via the blood to the adrenal gland. The adrenal cortex is the specific target for ACTH, which produces more glucocorticoids, chiefly cortisol, and mineralocorticoids, namely aldosterone. As you have seen, glucocorticoids have pronounced metabolic effects on the liver, while the mineralocorticoids target the kidney to retain more water and sodium, resulting in increased blood pressure and blood volume.
Which of these conditions would promote aldosterone release from the adrenal glands?
A drop in blood pressure is sensed in the kidney. A drop in blood pressure would cause the kidney to release renin, a hormone that will eventually promote the release of aldosterone from the zona glomerulosa of the adrenal cortex.
Drag the hormone on the left to its correct function on the right.
Each of these hormones plays a distinctive role in the body. Epinephrine, along with norepinephrine, target the cardiovascular and respiratory systems, producing increases in heart rate and blood pressure, along with increased dilation of the respiratory bronchioles. Blood glucose and metabolic rate increases are also important functions of epinephrine. Corticotropin-releasing hormone and adrenocorticotropic hormone are tropins; that is, their target organs are other endocrine glands. Corticotropin-releasing hormone targets the anterior pituitary, causing the release of adrenocorticotropic hormone; this, in turn, affects the adrenal cortex to release glucocorticoids and mineralocorticoids. Lastly, cortisol and aldosterone are the chief secretions of the glucocorticoids and mineralocorticoids, respectively; cortisol targets the liver for various metabolic effects, while aldosterone impacts the kidneys, causing them to retain more sodium and water.
What type of cell is shown at letter C?
Follicular cells of the thyroid line the follicles and manufacture the materials within them.
Damage of which of the following brain structures could cause central diabetes insipidus?
Hypothalamus
Drag and drop the items below to the appropriate bin, depending if the item is associated with the short-term or long-term stress response.
Short-term stress response droppable: - Triggers the fight-or-flight response - Targets the adrenal medulla - Hormone released: epinephrine - Activated by neural stimuli Long-term stress response droppable: - Increased blood pressure; increased protein and fat catabolism - Hormone released: glucocorticoids - Targets the adrenal cortex - Activated by hormonal stimuli The long-term and short-term stress responses vary in their mechanisms: in the short-term response, stressful stimuli target the hypothalamus, which activates the sympathetic nervous system, ultimately impacting the adrenal medulla. The adrenal medulla releases the catecholamine hormones - epinephrine and norepinephrine - which result in many of the effects associated with the "fight or flight" mechanism. In the long-term response, stressors to the hypothalamus cause the release of corticotropin-releasing hormone, which targets the anterior pituitary gland. Adrenocorticotropic hormone travels in the blood and targets the adrenal cortex, resulting in the production of mineralocorticoids and glucocorticoids. The mineralocorticoids impact the kidney with increased sodium and water retention, while the glucocorticoids target the liver to increase production of glucose from fats and proteins, or mobilize them for energy.
Your patient has been admitted to the intensive care unit with a severe head injury. As you monitor his urine output, you find that it has fallen sharply. Lab tests indicate that his serum osmolality is lower than normal (i.e., his plasma is too dilute). What should you suspect?
Syndrome of inappropriate antidiuretic hormone (SIADH)
Which of the following occurs in situations where different hormones produce the same effects at the same target cell and their combined effects are amplified?
Synergism occurs when more than one hormone produces the same effects at the target cell and their combined effects are amplified. For example, let's say both hormone "A" and hormone "B" cause the liver to release glucose into the blood. When they act together, the amount of glucose released might be 150% of what is released if each hormone acts independently.
This diagram shows how the body keeps blood glucose at a normal level.
T Prolonged exposure to high hormone concentrations would result in down-regulation (not up-regulation), which involves a decrease in the number of receptors for that hormone. Down-regulation desensitizes the target cells, so they respond less vigorously to hormonal stimulation, preventing them from overreacting to persistently high hormone levels.
Which gland secretes the most important hormone controlling calcium balance in the blood?
parathyroid Parathyroid hormone (PTH) is the single most important hormone controlling calcium balance in the blood. Falling blood Ca2+ levels trigger PTH release, and rising blood Ca2+ levels inhibit its release. PTH promotes bone resorption to release Ca2+ into the blood, inhibits excretion of Ca2+ in the urine, and stimulates the synthesis of Calcitriol, which in turn increases absorption of Ca2+ from our diet.
The word root _____ means feeding or eating.
phag
The word root ____ means phosphate or phosphorus.
phospho
An enzyme that degrades second messengers like cAMP or cGMP is _______.
phosphodiesterase
Cyclic AMP is degraded by __________.
phosphodiesterase Phosphodiesterase degrades cyclic AMP into AMP.
Water-soluble hormones affect target cells by binding to __________.
plasma membrane receptors Water-soluble hormones bind to specific receptors in the plasma membrane, whereas steroid hormones bind to cytoplasmic receptors.
Overeating, or ______, is a sign associated with diabetes mellitus
polyphagia
Overproduction of urine, or _____, is a sign of diabetes mellitus.
polyuria
Which hormone stimulates mammary glands to produce milk in nursing mothers?
prolactin Prolactin stimulates the mammary glands of the nursing mother to produce milk. After birth, the infant's suckling stimulates release of prolactin-releasing factors in the mother, encouraging continued milk production.
Which of the following pairs correctly matches the adrenal gland structure with the class of hormones it produces?
zona glomerulosa: mineralocorticoids The zona glomerulosa produces mineralocorticoids
